using tapply on a data frame in a function
eric lee wrote:
Hello, I'm trying to use tapply to find group means in a function. It works outside of a function, but I get the error message from the following code: "Error in tapply(index, cluster, mean) : arguments must have same length." Any suggestions? Thanks.
This is neither caused by tapply, data frames, nor functions....
You are trying to use a character string ('value1') as if it were a
variable name. It wouldn't work either to say tapply('value1', cluster,
mean) would it?
You might be looking for tapply(framename[[index]],....), or
with(framename, tapply(get(index), ....)),
or maybe some concoction involving substitute().
eric
d <- data.frame(cbind(cluster=1:2, value1=1:10, value2=11:20))
d
FindClusterTraits <- function(framename, index){
MeanCluster <- with(framename, tapply(index, cluster, mean))
return(MeanCluster)
}
d2 <- FindClusterTraits(d, 'value1')
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